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Interior and exterior lighting
Addressing both interior and exterior lighting, this credit seeks to reduce light pollution that can block our view of the night sky and cause human health problems as well as ecological problems for many birds, insects, and other animals. Light pollution often represents nighttime lighting that isn’t needed, wasting energy while causing light trespass and contrast, reducing visibility.
Better lighting = Better safety, less energy
Many people think that more lighting means better nighttime safety and security. However, too much exterior...
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58 Comments
Sample site plan
I think it would be good to show a sample submittal with a plan view of the site. Most people seem to think this credit is easy since the calculations they've seen were done wrong. The most common mistake is showing an accuracy of 0.1 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. rather than 0.01 fc for the light trespass calculation. Second most common being only measuring horizontal light rather than horizontal and vertical light.
Maybe another file showing differences between light fixtures based on lamp wattage, pole height, house side shield, LED vs HID, and segmented vs hydroformed optics. Showing isometric contours under each fixture with values at 0.01, 0.1, 0.5, 2, 5 fc. It would only be based on horizontal but it's a nice visual way to see the light distribution. It would help to overlay the calcs onto a small parking lot to give people some perspective of scale.
Tristan Roberts replied Editor – LEEDuser, BuildingGreen, LLC Jul 07 2009
Bill, that would be great. We don't have a sample submittal like what you're asking for, but we're working on it. If anyone out there has a sample like this, please contact us using the "contact" link at the bottom of the column to the right.
Shillpa Singh replied Senior Consultant, YRG Sustainability Jul 14 2009
Bill,
Thanks for your great comments.
Light trespass calculation requirements vary by site location. All projects have to demonstrate a maximum limit of light intensity of 0.01 horizontal foot-candles at either site boundary (in case of LZ1) or 10'-15' beyond site boundary (LZ2- LZ4). This necessitates the measurement of lighting levels and simulation in photometric studies to an accuracy of 0.01 foot-candles, but notably only for horizontal lighting levels. However, if a project has demonstrated lighting levels of 0.0 foot-candles at site boundary then the light intensity of 0.0 is sufficient for credit compliance purpose.
We certainly agree on importance of illustrating through images and drawings. We are in the process of adding more documentation approved for LEED certification including site photometric study and light fixtures photometric data of lumens at maximum candela angle. We hope to get these sometime soon.
Bill Swanson replied Jul 16 2009
Thanks for the replies. At the property boundary a horizontal and vertical calculation is required. I have never seen a submital which showed the vertical calculation. At 10-15' beyond the property boundary only the horizontal calculation is required.
This is why it helps playing around with the software. A value of 0.0 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. can be 4 times higher then 0.01 fc because the software rounds. A value of 0.049999 will show up on the calculation grid as 0.0 fc when the accuracy is set to only show one decimal space. There is usually a 20-30 foot difference between 0.049 and 0.01 fc. So it makes a large difference in the layout of lights. I agree that many projects have recieved this point by showing 0.0 fc. I have also seen some which showed 0.1 fc. Because the review staff does not know any better does not mean I, as the designer, have a lower level of responsibility to meet the credit requirements. I think they are learning and future submittals may not be as easy.
I hear this site is going toward fee based for access. If I provided documents showing these items would I be able to get membership for a few years?
John Beeson replied Chief Mystic in Resident, betterENVIRONMENT, LLC Feb 17 2010
LRG for BD+C states maximum limit of light intensity of 0.01 horizontal foot-candles at 10' beyond site boundary for LZ2 and 15' for LZ3-LZ4. Is this accurate or is the note above?
Bill Swanson replied Feb 18 2010
John, you and Shillpa are correct. The language of the credit states 0.01 horizontal fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. beyond the site boundary at the distances you've stated.
But most of the projects that have earned this point have done so in the manner Shillpa has stated. Many reviewers don't understand lighting or the software and see 0.0 fc and think it means absolute zero. So they assume anything beyond the site boundary is still zero light. Does this help?
Bill Swanson replied Feb 18 2010
Think of it like having a hand full of feathers and some asks how many grams does it weigh? One person uses their bathroom scale and says it has a weight of 0.0 kg. Another person uses a more sensitive scale and says it weighs 25 grams. The difference is in the accuracy of measurement. I seem to have difficulty explaining that while the feathers are light they still have some mass. Don't tell me they weigh zero grams because the bathroom scale said they weigh 0.0 kg. Most reviewers just see zero on the paper and move on to the next credit.
interior light leak reduction
Please address this in a paragraph or two.
Tristan Roberts replied Editor – LEEDuser, BuildingGreen, LLC Jul 14 2009
Here are a couple of the most useful tips on reducing interior light leakage, from our "Getting It Done" section:
Be aware of all requirements for interior lights so that fixtures do not direct light through windows to the outdoors. Identify locations where fixtures might have a direct line of sight to a window or other opening. The lighting designer should either eliminate those fixtures from the design, provide shades to prevent more than 10% of light from shining outdoors, or include controls to reduce the input power by 50% between 11 p.m. and 5 a.m.
Fixtures that throw 50% or more of the cone of light out a window are likely to present problems.
victoria toplas replied Jul 06 2010
quick question on this theme as to definitions:
interior lighting is all light fittings attached to the interior of the building? or would a light fitting that serves to illuminate building structure against a fully glass facade count as outdoor lighting, since much of the light escapes out from the building and the purpose is (arguably) to be seen from outside?
Bill Swanson replied Jul 06 2010
Interior lighting = All light fixtures attached to the interior of the building.
If you want to light the structure like this and earn this credit then mount the fixture close to the glass and aim it so all direct light goes inward. There are some linear fluorescent or led grazing lights that can do this.
victoria toplas replied Jul 06 2010
thanks very much Bill! just so im sure I've understood, as interior lights they should then have their input power reduced by 50% (or be shielded) overnight, and would not need to be simulated in the exterior lighting calculation of the horizontal footcandlesHorizontal footcandles occur on a horizontal surface. They can be added together arithmetically when more than 1 source provides light to the same surface., since that only speaks of external lighting. Is that correct?
Bill Swanson replied Jul 06 2010
You only need to shield or reduce power if the light directly goes out of the windows.
These interior lights do not need to be simulated in the exterior lighting calculation.
victoria toplas replied Jul 06 2010
fantastic, thanks for your help!
Harvard's?
I'm sure you are familiar with Harvard's GreenCampus Resource? If not, check it out: http://greencampus.harvard.edu/theresource/
They have sample template submittals for all of their projects as well as the same "Bird's eye", "Credit language", "getting it done" features.
So, that makes me think then about this LEEDuser website. I can see how somethings are different than what is available for free, but how will someone determine why they should pay for this service?
Tristan Roberts replied Editor – LEEDuser, BuildingGreen, LLC Jul 24 2009
John, great question. The Harvard site is great; however, there are some key differences between that and LEEDuser.
1) LEEDuser guides you through LEED 2009, which you'll have to use for all newly registered projects, while Harvard's projects are all NC v2.2 or earlier. It will be a while before they have LEED 2009 projects up.
2) We'll be covering all credits for all 5 current LEED 2009 rating
systems -- not just the ones that the Harvard projects happened to
attempt.
3) Harvard's is an internal resource that they have chosen to publish publicly. LEEDuser is built from the ground up for the general public and we will go the extra mile to keep it updated and support you in using it.
4) LEEDuser offers numerous other features not found on the Harvard site, such as this user forum, links to products from the GreenSpec directory, original process diagrams to guide you through complex credits, and blank templates alongside sample filled-out templates.
Basically LEEDuser is dynamic and we will actively grow it with the help of our many expert partners. Keep us posted on how the site works for you.
Bill Swanson replied Jul 27 2009
Harvard's GreenCampus Resource is what I was refering to when I said the submittal information I've seen for this credit has been done wrong. I'm trying to limit my criticism because I don't want them to remove the information they're providing. It's always easy to pick apart the work others have done, and I don't want to discourage the efforts others have made at public disclosure. (When was the last time your work was viewed by a million colleagues?) If it wasn't for Harvard's disclosure USGBC would still be ignoring my public comments to change this credit because the 0.01fc requirement is too restrictive. I'm not thrilled with the new direction they're heading in LEED-ND.
Vertical Footcandles: How High the Measurement
There has been some conversation here about the concept of vertical footcandlesVertical footcandles occur on a vertical surface. They can be added together arithmetically when more than 1 source provides light to the same surface.. Across the industry, this seems to be an issue that is not very well understood. Vertical footcandles are a measure of light intensity at the site boundary across a vertical plane. So if horizontal footcandlesHorizontal footcandles occur on a horizontal surface. They can be added together arithmetically when more than 1 source provides light to the same surface. what you get if you take a light meter and hold it parallel to the ground, Vertical footcandles is the reading you would get if you hold the light meter perpendicular to the ground (parallel to the light poles and the building walls). If you are standing erect and looking into the site from the site boundary, your eyes are detecting primarily vertical footcandles. I'll post a drawing to illustrate what I'm talking about.
The next question is: how high off the ground should you take your measurements? Unfortunately, LEED is silent on this point. In talking to Dane Sanders at Clanton Associates, he confirmed that there is not much guidance here, but that they have been using ground level and have had several projects successfully earn this credit.
Dane also shared a sample site photometric plan for vertical footcandles for the Hannaford supermarket that just earned Platinum. I've posted that to the Documentation Toolkit.
Hope that helps.
Bill Swanson replied Sep 01 2009
In my public comment for LEED-ND I suggested measuring the vertical fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. at 5' above grade to represent eye/window level to measure glare. The response back was that measurements are suppose to be measured at grade level for both horizontal and vertical fc calculations. They also said future guidebooks would be more clear about the height of the calculation grid.
I try to explain the difference between horizontal and vertical this way. Horizontal light is how much you see when you're laying on the ground on your back looking straight up. Vertical light is how much you see while standing up looking into the site. So if a light pole is directly above you it will be much brighter to you while you're laying on your back then when you're standing up. And a car's headlights will be appear much brighter while standing up than when you're laying on your back.
Thanks for the sample site. Can you ask Dane what light fixture, wattage, and height this is. I'm shocked to see on the left side of the site at the drive entrance a measurement of 0.0 fc on the front and side of the light fixture when the points are as close as only 40' away from the fixture. Other points around the site show more light on the backside of the fixture.
Jean Marais replied b.i.g. Bechtold INGENIEURGESELLSCHAFT MBH Sep 25 2009
Page 135 of the BD&C Userguide suggests, "Calculate the vertical light levels along and above the site boundary to a height of at least the highest luminaire on the site."
Demonstrating LPD Compliance
Can I use the ASHRAE table and methodology of demonstrating LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. compliance? SS8 states that “Lighting power densities must not exceed ANSI/ASHRAE/IESNA Standard 90.1-2007 (with errata but without addenda) for the classified zone”. ASHRAE provides a table and methodology of demonstrating LPD compliance that is relatively simple, flexible, and straightforward. The methodology shown as Example Table 2 in the LEED 2009 Reference Guide seems much more difficult in comparison. The Guide appears to require that each Application Area (Application Area = Classified Zone? – this isn’t defined in the Guide) be fully calculated as an individual element. For a site that contains multiple Application Areas, and has individual lights that spill across several Areas, the documentation task is formidable. Further, the Guide doesn’t appear to include the provision for tradable areas that is in ASHRAE, so a localized ‘hot spot’ may render the entire project out of compliance when the net power over the net area is actually fine.
Also, Example Table 2 in the Guide contains references to Required LPD Reduction that appears to be a holdover from LEED 2.2, and is not applicable to LEED 2009. Am I misinterpreting something?
Joshua Radoff replied Principal, LEEDuser Primary Author, YRG sustainability Sep 28 2009
Dean,
You're right about the example in the reference guide. It's overly complicated and makes it seem like tradable areas are not allowed. But you should ignore the unnecessary complexity of the example and follow the ASHRAE standard. Tradable surfaces are indeed allowed, which means you can aggregate and take a weighted average of all of the tradable areas.
In terms of the Classified Zone, that refers to the IESNA RP-33 Zones (LZ1 - LZ4) which deal with urban to rural locations and the different requirements per Zone.
Hope that's helpful.
Josh
Automatic shut off system
one of the project has office building with attached storage warehouse.the office area is 3500 sq ft and warehouse is 25000 sq ft.the office is conditioned and warehiuse is unconditioned space.for LEED certification we are including the warhouse also.for automatioc shut off mandatory provisions,the area should be 5000 sq ft or more.here for all calculation we are considrting only office area,because the warehouse is only storage .If we are considering only office area .is it necessary to provide Automatic shut off system to comply the ASHRAE 90.1-2004/2007standards?
Sherry Bonelli replied LEED Project Manager/Consultant, BudSprout LLC -- SucceedAtLEED.com Feb 15 2010
We ran into that situation with one of our projects -- part of the builidng was office with an attached garage. We ran different scenarios to determine if it was more beneficial to include the garage or exclude it. In the end we decided to exclude the garage. On all of the drawings we submitted, we outlined the LEED project boundary and identified that the garage was NOT part of the LEED project boundary.
Sherry
www.SucceedAtLEED.com
exterior lighting
Hi all, can you please tell me which is the best suitable software to demonstrate the compliance for horizontal and vertical footcandlesVertical footcandles occur on a vertical surface. They can be added together arithmetically when more than 1 source provides light to the same surface. requirements to USGBC for Light Pollution Reduction credit.
Joshua Radoff replied Principal, LEEDuser Primary Author, YRG sustainability Dec 06 2009
Joshua,
I checked with Dane Sanders, lighting guru from Clanton & Associates, and he reports the following:
We use a lighting calculation program called AGI32 from Lighting Analysts, Inc. This is great software for lighting designers, but may be more than necessary for someone who does not design lighting as their primary service. There is a free lighting calculation software called Visual that can be downloaded at: www.visual-3d.com.
Hope that helps,
Josh
Jean Marais replied b.i.g. Bechtold INGENIEURGESELLSCHAFT MBH Feb 03 2010
Some other softwares are:ReLux;DIALux (free);Rayfront;and some time in the next year or so DesignBuilder.
My main problem is that the geometries have to be re-created, even when you can import 3d dxf data in some programs and snap to the points quickly to create the geometry. For large projects this is still painfull.
I currently use DesignBuilder for Energy and Thermal Building Simulations and can't wait until the photometrics is fully intergrated. At the moment you can use the calculation engine (EnergyPlus) to calculate some daylighting information and get the results in csv format, but displaying this on the 3d model in DesignBuilder still needs intergration.
Dark Sky Ordinance vs ASHRAE/IESNA 90.1 2007
Hello All,
I have a project that is required to meet its own jurisdictional dark sky ordinance. In reviewing the ordinance, it appears to be very similar to IESNA in its approach, but until we actually go through both the calculations, we will not be sure which one is more stringent.
We would like to comply with the most stringent requirements and submit the information for both entities - LEED and AHJ (Authority having Jurisdiction)
Any ideas on how to approach this situation?
Will LEED accept a compliance to local dark sky ordinance?
Any help would be greatly appreciated.
Thanks.
Prem
Jean Marais replied b.i.g. Bechtold INGENIEURGESELLSCHAFT MBH Feb 03 2010
Try working outside of the USA. I have this problem on everything and guess what? I have to do every thing twice! Once for local norms and codes, and once for "LEED" norms and codes, meaning ASHRAE, IESNA, Green Label, etc. And don't forget: only 77% of all LEED registered square footage is actually in the USA.
Sorry, that doesn't help much.
For starters you would have to look at the definitions, such as zone definitions. You may end up choosing a more stringent zone (say urban) to make sure you conform. Without the details, it's difficalt to tell.
Jean.
Dark Sky Calcs
If you've got full cutoffA full cutoff luminaire has zero candela intensity at an angle of 90 degrees above the vertical axis (nadir or straight down) and at all angles greater than 90 degrees from straight down. Additionally, the candela per 1,000 lamp lumens does not numerically exceed 100 (10%) at an angle of 80 degrees above nadir. This applies to all lateral angles around the luminaire. fixtures you are usually set. However, if you have a situation like we had earlier, with some angled spotlights, you've got a problem. We actually took IES data and converted it using a homemade spreadsheet. We had to take candela info from the IES file and convert it to a different angle mathematically. Not an easy task! That's the hard way. I'd like to hear about the easy way!
Interior Light Leak Reduction - High Bay Warehouse
Hello all,
Regarding light leaking from a high bay warehouse with clerestory windowsPronounced and sometimes spelled "clear-story," these are vertical, or close-to-vertical, windows high in the wall of a building that bring daylight deeply into the building and, if operable, can help ventilate the space. above the dock doors. The situation is as follows:
1) T5 High Bay Lighting installed at the roof deck at approximately 37' off finished floor.
2) Center of clerestory 4X4 window at approximately 25' off finished floor (29' off exterior grade).
3) T5 Lighting is "shielded" by the walls above the clerestory windows (12' +/- delta in height).
4) Hours of operation will exceed the 11:00 PM limit and all lights will be used for operations during the after hour period.
5) Blinds are not an option.
6) Dimming is not an option.
7) ShieldingShielding is a nontechnical term that describes devices or techniques that are used as part of a luminaire or lamp to limit glare, light trespass, or sky glow. is our only option and this is created by the delta in height noted above.
So, given these parameters, here are the questions at hand:
1) LEED specifies "direct line of sight to any non-emergency luminaires must have shielding." What area do we use to establish a direct line of site? Anywhere in the defined site? Outside the site?
2) Do they consider line of site horizontal or at any angle that allows one to look into the window?
3) If someone is standing is standing outside of the building and can see a light fixture inside, does that automatically disqualify?
4) If question three doesn't automatically disqualify, then how and where do we measure the percentage of light coming out of the windows, i.e. do we use a light meter in a vertical position while standing in a lift bucket? if so, how far away from the window and at what height?
5) How can we calculate and/or measure the amount of light escaping through the windows?
Please forgive my dissertation. I believe this credit was designed more for more of a curtain wall or storefront glass assembly so our warehouse scenario is not in the norm and as always, each project if different.
I have sent this question in to GBCI and hope to hear something soon (yeah right).
Thank you in advance for any feedback.
Lauren Glasscock replied Sr. Sustainability Professional, KEMA Services, Inc. Feb 08 2010
Hi Dan,
The first bit of information that you need is a cutsheet of the proposed lighting fixture(s). Each cutsheet usually includes a small photometric of the light fixture. On the cutsheet there is also a small char that shows the way the light is diffused from the light fixture. Typically this chart is shown on the right.
Once you have this information you can find out how much "travel" the light has from the light fixture. My electrical engineer friend considers the light travel to be the maximum distance that the light will "reach" once it is turned on.
What you are looking for is how much area the light really covers and -- dependent on the area that the light covers -- how much much of it is going toward the outside.
Typically if you can justify that there is little to no light escaping to the outdoors you are in good shape. I understand that these high-bay lighting systems tend to be a little bit tricky because the additional height requires a stronger light to provide the right amount of lumens in the space.
Bill Swanson replied Feb 18 2010
Usually these highbay fixtures have 2 or 3 ballasts. While dimming might not be an option you could put half of the ballasts near the perimeter on occupancy sensor. This will meet the 50% light reduction requirement. Your fixture manufacturer probably has an occupancy sensor for warehouse applications designed for mounting directly to the fixture.
I've heard of some companies doing this to all of their high bays for all hours so full lights are only on when the forklift is in the aisle. Saves a bit of energy even if the energy model won't show the savings.
Dan Prows replied Feb 22 2010
Thanks Bill and Lauren.
We use occupancy sensors in many cases. If I remember correctly, option 1 seemed non applicable on this project as most of the isles will be in use during the entire night. As such, the lights, although fitted with sensors, will remain on most of the night at 100%. I suppose the question I should be asking is, "Does the end result matter or is just having the sensors suffecient to satisfy the credit?" Thoughts?
Interior Lighting - no "Non-business hours"
I am working on a project that runs 24-7, every day of the year. Has anyone heard of exceptions made in terms of meeting the Interior Lighting requirement that "all non-emergency interior lighting be automatically controlled to turn off during non-business hours"?
It's a hospital and we wouldn't be able to meet the Interior Lighting component through the maximum candela route.
Tristan Roberts replied Editor – LEEDuser, BuildingGreen, LLC Feb 10 2010
I don't have experience with this situation, but it seems like a situation that good be addressed straightforwardly through a narrative explaining that there are no non-business hours, so the requirement is met.
Mara Baum replied Sustainability Coordinator, Anshen + Allen Architects Feb 10 2010
Hi Lauren - many hospital spaces have no non-business hours. Many hospital spaces don't operate 24/7, and it's really important to identify which are which and design accordingly.
Jean Marais replied b.i.g. Bechtold INGENIEURGESELLSCHAFT MBH Feb 11 2010
Check these out! www.permalight.com
Like glow in the dark stickers equivalent emergency "lights"
Tristan Roberts replied Editor – LEEDuser, BuildingGreen, LLC Feb 11 2010
Jean, before you get too excited about photoluminescent exit signs and lights I would recommend reading two recent articles from Environmental Building News (which our company also publishes, btw):
The Evolution of Exit Signs (and Why the Latest is a Bad Idea)
Photoluminescent Exit Signs Not Energy Efficient
The first article is a great white paper on the topic that you can get for a $12.95 weekly subscription; the second one is a free news article.
Jean Marais replied b.i.g. Bechtold INGENIEURGESELLSCHAFT MBH Feb 12 2010
Great reply. Obviously if they were perfect, we wouldn't have the normal type installed anywhere anymore. But I am as you say exited by the idea. Juging by how fast they loose their glow, it's almost like having a glorified reflector.
I can just imagine a scenario where there's a power cut, the emergency lights jump on and these exit sign reflectors light up in the glow of the emergency lighting... Probably still worth considering. As the other 27% of the registered ft² of LEED projects lay outside of the USA, the legislation is also to be considered in many more cases than one can imagine.
I'm also always scepticle of the influence of economic pressures that suppress change in technology. The idea of electric cars was also there at the time of the first automobiles.
Mark Meaders replied Sustainable Design Project Manager, HDR Architecture, Inc. Mar 09 2010
Look on pg. 134 of the LEED BD+C 2009 Reference Guide. It states that 24-hour operations are exempt from the after-hours override automatic shutoff, and thus must follow Option 2.
Hope that helps.
Footcandles at the LEED Boundary
I've got a project trying to meet the requirements of LZ2 under this credit. the LEED boundary abuts the public rights-of-way at all points. It is essentially an island between streets. The language in the referece guide states that if this is the case, then the light trespass requirements may be met relative to the curb line instead of the site boundary. Does the "curb line" mean the curb line across the street or the curb line on which our LEED building sits, which is already our LEED boundary?
Bill Swanson replied Feb 12 2010
The curb line refered to is the one your building is sitting on.
They also allow a little flexibility for Code required emergency egress lights. In this situation the requirements can be waved at the site boundary for EM lighting but you are still required to meet the 0.01 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. level at 10' beyond the boundary. Good luck with that.
Brittany McCollum replied Intern, Viridian Feb 12 2010
I guess I'm not clear on why that language is in there if the boundary and the curb line both end at the public rights-of-way.
Do you happen to know how to use IESNA RP-33 to establish the zone a project site falls under? From LEED reviews we've been pushed to use population densities to determine the zone, but that doesn't seem to always make sense. For example, this current project is the entrance of a military base in a heavily light industrial area. Population density puts us at LZ2 - Low (Residential Areas) but it seems LZ3 - Medium (commericail/Industrial, High-Density Residential) would be a better fit. How else can you make the case for this area besides through population density.
Lauren Glasscock replied Sr. Sustainability Professional, KEMA Services, Inc. Feb 12 2010
Hi Brittany,
Regarding the curb line, is your project a LEED-NCv2.2 project or a LEEDv3 project because I believe the curb line rule is slightly different for the two systems.
Regarding the LZ, I've always just used population density. Are you way off from falling under LZ3 in terms of the population density?
Brittany McCollum replied Intern, Viridian Feb 15 2010
The project is v2.2. The population for the Zip Code at my site is 604. LZ3 needs 3,000 in v.2.2. I've been using www.city-data.com as an estimate of density. Is there a better resource than this?
Lauren Glasscock replied Sr. Sustainability Professional, KEMA Services, Inc. Feb 15 2010
Hi Brittany,
Regarding LZ: As long as you're using the latest US Census data then I think you're using the correct information for determining your lighting zone. You mentioned that your project is in a "heavily light industrial area". LZ-2 includes "light industrial" so I think it could be argued that it should fall under LZ-2. LZ-3 is supposed to be for "high density urban neighborhoods". I believe you could try to make a case for why your project should fall under LZ-3 by providing a more detailed narrative, though, I can provide no assurance that it would pass.
Curb Line: Since your project is a LEEDv2.2 project the curb line just becomes your LEED Site Boundary for SSc8 in instances in which your project abuts public rights-of-way. This -- based on your description, sounds like your entire site.
Fun factoid for LEEDv2009 (all zones), "Illuminance generated from a single luminaire placed at the intersection of a private vehicular driveway and public roadway accessing the site is allowed to use the centerline of the public roadway as the site boundary for a length of 2 times the driveway width centered at the centerline of the driveway."
Some ideas for aiding in your compliance: Only light fixtures that fall within your LEED Site Boundary would be included in the photometric calculations. Also, as Bill mentioned there are some exceptions allowed for emergency egress. The last thing I would mention is a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide dated 12/15/06 which allows the project to be out of compliance at the site boundary in two instances so long as the project is in compliance in all areas 15' beyond the LEED Site Boundary (extrapolated for 10' for LZ-2).
Bill Swanson replied Feb 15 2010
Brittany,
Please write suggestions to USGBC next time they have a public comment on LEED. Your situation is difficult and I feel shows many of the flaws with this credit as currently written.
- Who picks the lighting zone? Most people in your situation just pick LZ3 because it's easier to comply. The LZ's are selected based on feelings, not data. It feels industrial, must be LZ3.
- Why does it matter if my site light spills onto a public street that may be lit?
- The allowance of the site boundary to centerline of road at driveway entrances is of almost no benefit. (Tristan, could you post my Drive Entrance.pdf I sent you). Even short, low wattage fixtures have a large 0.01 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. footprint, covering a 95'x160' area.
- The allowance of EM lighting at the site boundary but not beyond the boundary is of almost no benefit. Light is a bit like sound. You can direct it and control it only so much, there's a lot of spill into nearby areas. 10 or 15 feet is very close on site measurements and most Inspectors want the EM lighting to extend at least 10' from the door. Again, it's only a street.
Light trespass in a parking lot addition
My client is expanding an existing building onto an adjacent tract. Our LEED boundary is the interface between the new and existing buildings, extended across what was an existing parking lot. The project conforms to LEED requirement for LZ3 along the entire boundary with other owners, but, of course, across the parking lot we don't create a dark zone to satisfy LEED. The multiple building application guide doesn't offer too much help, although it does seem to say that we could demonstrate compliance around the entire site (old and new building and adjacent grounds). Someone suggested that I can set a LEED boundary through the parking lot that differs from the LEED boundary for other credits. This seems strange, and I would still have to 'turn off' the existing lights to find a boundary at which the new lights meet the trespass limit.
Bill Swanson replied Mar 02 2010
Yes, you can treat the new and existing site as a campus. If the campus is as a whole compliant with this credit then you can earn the point. And yes, this campus boundary can differ from the site boundary shown for other credits.
David Sheridan replied Principal, Aqua Cura Mar 02 2010
I want to avoid doing an exterior light study for the entire campus, because of the cost and the likelihood that the campus would not comply. It's an old industrial site. The manufacturer is doing the expansion as a LEED project, but would not be willing to retrofit the entire campus.
Jonathan Weiss replied Jun 16 2010
My reading of the Multiple Buildings / Campus application guide is that the owner needs to have a Site Lighting Master Plan in place, which means that they intend to comply with all the requirements on a campus basis. If my project is the first one on the campus to go for LEED, I would think the owner has time to implement the master plan - e.g. they don't need to go through the entire campus and change out all the fixtures. Otherwise, it wouldn't be a master plan, it would be a prerequisite enabling project. Any thoughts? Or is this wishful thinking...
Bill Swanson replied Jun 16 2010
I have seen projects earn this credit in the manner you described. All their master plan consisted of was a copy/paste of this credits requirements and a promise to comply with all future work. Looking at the site shows several large parking lots right next to public streets. There's no way they'll be able to light those lots and avoid spill light regardless of any promise made.
I am probably in the minority but I disagree. I think the whole site or campus has to comply at time of submittal, with a promise that any future work will also comply.
Per NC2.2 CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide 10/16/2008: "...Per the LEED-NC Application Guide for Multiple Buildings and On-Campus Projects (AGMBC), this credit can be attempted at the campus level, negating the need to meet the light trespass thresholds along parcel property lines as long as the requirements are met for the campus as a whole. ..."
Jonathan Weiss replied Jun 16 2010
Thanks, Bill - really good comment. I think there is a distinction, however, between making a promise that can't be met - like you suggest above with a parking lot adjacent to a public boundary -- and making a promise that you will be able to implement over time for budget reasons. On some large campuses, the revision of lighting for the whole campus would be more than the entire project budget for our LEED project itself. And on others we would not be able to keep those promises due to the configuration of the campus.
Flagpole Restrictions
Are flagpoles exempt from this criteria. I did a word serach of the entire LEED Reference Guide and it does not address this condition. Our firm has several DoD and school projects with flagpoles.
Mark Meaders replied Sustainable Design Project Manager, HDR Architecture, Inc. Apr 09 2010
Check out v2.0/2.1 CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide Ruling dated 7/29/2005 - it states lighting the American flag is acceptable if a maximum of 3 luminaires (utilizing less than 3500 initial lamp lumens each) is used for only one pole location on the property, and only in areas of high ambient brightness. The luminaires must be controlled such that they will be automatically shut off during after-hours and during post curfew periods. Otherwise, you need to follow the universal custom of displaying the flag from sunrise to sunset with no lighting.
Lauren Glasscock replied Sr. Sustainability Professional, KEMA Services, Inc. Apr 11 2010
I would agree with Mark although I don't think you can technically use non-project specific CIRs anymore in LEEDv2009. Despite this, I would assume you can use the CIR as a reference.
The CIR:
7/29/2005 - Ruling –FLAG LIGHTING
Flag lighting has been a controversial topic within LEED and CIRs. Based on a further interpretation of the CIR ruling dated 3/14/2003, lighting the American/National flag has been deemed acceptable under LEED if a maximum of 3 luminaires (utilizing less than 3500 initial lamp lumens each) is used for only one pole location on the property, and only in areas of high ambient brightness. The luminaires must be controlled such that they will be automatically shut off during after-hours and during post curfew periods.
Bill Swanson replied Apr 12 2010
I never thought this CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide helped much. People want the flag lighted all night because no one takes the flag down every night.. Turning it off after-hours is considered unpatriotic.
The US Flag Code states, "It is the universal custom to display the flag only from sunrise to sunset on buildings and on stationary flagstaffs in the open. However, when a patriotic effect is desired, the flag may be displayed twenty-four hours a day if properly illuminated during the hours of darkness."
I have always counted the flag lighting in with my total site calculations. It's amazing how little will use-up the uplight allowance for the site. I do not often earn this credit.
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